Palm trees are known for their ease of care and low maintenance needs, particularly in areas of the country with Mediterranean or subtropical climates. But palm trees also can be damaged, even fatally, by various fungal infections, other diseases and insect infestations.
Diagnose the problem before you consider any course of care. Carefully inspect the palm tree and write down the symptoms in checklist form. Include such obvious signs of distress as browning leaves and wilting.
Consult with a palm expert---call any local nursery for a referral---and treat according to the affliction.
Treat your palm tree with chemicals as determined by the palm expert with whom you are consulting if your plant has bud rot, which makes the fronds of a palm tree wilt and die, with the rest of the tree dying shortly thereafter. Bud rot typically affects Mexican and California fan palms, particularly in the summer.
Inject your palm tree with the chemical oxytetracycline once every three months if the problem is caused by lethal yellowing, which causes the fronds of a palm tree to turn yellow.
Use insect killer, ideally a specialized one that is available through palm dealers, to rid your palm of the larvae of a beetle known as a budworm that feed on the flowers of various types of fan palms. The larvae are pinkish-green and measure about an inch long. Moths are light brown, and there's a dark spot on each wing. Intense infestations can weaken and eventually kill a palm tree.
Treat your palm with imidacloprid (available under the brand name Merit) by applying it to the root system of the tree if your plant is attacked by royal palm bugs, which attack palm trees---chiefly, royal palms. Eggs are laid inside the folds of new palm leaves, and after hatching, the bugs start eating the leaves, creating unsightly yellow or brownish spots on the underside of the leaves. Ultimately the leaves die and the entire plant could succumb to a massive infestation.